fix(sample): update FinancialSample to use typed RelatedIdentifierNameEnum

ParameterListFinancialTransactions20240619.relatedIdentifierName is now typed as
RelatedIdentifierNameEnum? rather than string?, so the sample code must use the
enum member instead of a raw string literal.

Author: ProNotion

Source/FikaAmazonAPI.SampleCode/FinancialSample.cs

@@ -65,7 +65,7 @@ public IList<Transaction> ListFinancialTransactions20240619_ByEventGroup(string
                 new Parameter.Finance.ParameterListFinancialTransactions20240619()
                 {
                     postedAfter = DateTime.UtcNow.AddDays(-30),
-                    relatedIdentifierName = "FINANCIAL_EVENT_GROUP_ID",
+                    relatedIdentifierName = RelatedIdentifier.RelatedIdentifierNameEnum.FINANCIALEVENTGROUPID,
                     relatedIdentifierValue = financialEventGroupId,
                 });
         }